This invention relates generally to chemical dispensers for use in bodies of water. More particularly it relates to a pool chemical dispenser that is designed to float on the surface of a body of water and control the dissolving rate of a rapidly dissolving pool chemical, such as calcium hypochlorite, through the use of a unique tablet support and immersion system.
The use of chemical feeders to dispense water treatment chemicals into bodies of water, such as swimming pools and spas, have long been known. Such feeders have either floated on top, or just beneath, the surface of water. Other feeders have been employed in the flow loop of forced circulation systems to utilize the movement of water by the circulation pump after the water passed through a filter to dispense pool chemicals into the swimming pool or spa.
The most successful pool chemical dispensers have employed trichloroisocyanurate as the chemical that is dispensed into the water. Trichloroisocyanurate feeders have either utilized a floating container in which all of the material to be dissolved is continuously in contact with the water, have or utilized vertically extending chemical containers that can fully immerse only a portion of the pool chemical to be dissolved. Some feeders have been able to selectively control the dissolving rate of the pool chemical by vertically adjusting the depth of immersion of the cartridge containing the pool chemical in the water. This latter feature also provides a means to control the dissolving rate or introduction rate of the pool chemical into solution in the water. Since trichloroisocyanurate is a chemical which in tablet form dissolves slowly without leaving insoluble residue, it can be dispensed to swimming pools and spas at proper dosage levels using simple, low cost floating feeders.
However, where a fast dissolving chemical, such as calcium hypochlorite, is attempted to be used as the sanitizing chemical to treat water, controlling the dissolving rate of the pool chemical to provide a uniform introduction rate of the sanitizing chemical into the body of water over a length of time sufficiently long to be practical has presented a serious problem. Additional problems were presented to chemical feeder designers who attempted to utilize calcium hypochlorite as the pool chemical because of the insoluble residue formed when calcium hypochlorite dissolves in water. Prior floaters immerse the entire mass or tablet of pool chemical. Where substantially the entire tablet is calcium hypochlorite, this is impractical. This will cause increased formation of insoluble residues, such as calcium carbonate. This residue would either plug the feeding orifices from the cartridge or container to the surrounding body of water to prevent the flow of sanitizing chemical outside of the container, or would leave behind an aesthetically unacceptable trail of insoluble residue particles in the water.
Further, prior feeders gave no definite indication of when the pool chemical had been completely dispensed from the floating device and needed to be replaced. These feeders that do give some indication accomplish it by gradual inversion.
These problems are solved in the design of the present invention which embodies a pool chemical dispenser for use in the dispensing of a fast dissolving pool chemical, such as calcium hypochlorite, with an adjustable dispensing rate without leaving a detectable trail of insoluble residue.